1 /* FriBidi 2 * fribidi-bidi.h - bidirectional algorithm 3 * 4 * Authors: 5 * Behdad Esfahbod, 2001, 2002, 2004 6 * Dov Grobgeld, 1999, 2000 7 * 8 * Copyright (C) 2004 Sharif FarsiWeb, Inc 9 * Copyright (C) 2001,2002 Behdad Esfahbod 10 * Copyright (C) 1999,2000 Dov Grobgeld 11 * 12 * This library is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU Lesser General Public 14 * License as published by the Free Software Foundation; either 15 * version 2.1 of the License, or (at your option) any later version. 16 * 17 * This library is distributed in the hope that it will be useful, 18 * but WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 20 * Lesser General Public License for more details. 21 * 22 * You should have received a copy of the GNU Lesser General Public License 23 * along with this library, in a file named COPYING; if not, write to the 24 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 25 * Boston, MA 02110-1301, USA 26 * 27 * For licensing issues, contact <fribidi.license@gmail.com>. 28 */ 29 #ifndef _FRIBIDI_BIDI_H 30 #define _FRIBIDI_BIDI_H 31 32 #include "fribidi-common.h" 33 34 #include "fribidi-types.h" 35 #include "fribidi-flags.h" 36 #include "fribidi-bidi-types.h" 37 38 #include "fribidi-begindecls.h" 39 40 /* fribidi_get_par_direction - get base paragraph direction 41 * 42 * This function finds the base direction of a single paragraph, 43 * as defined by rule P2 of the Unicode Bidirectional Algorithm available at 44 * http://www.unicode.org/reports/tr9/#P2. 45 * 46 * You typically do not need this function as 47 * fribidi_get_par_embedding_levels() knows how to compute base direction 48 * itself, but you may need this to implement a more sophisticated paragraph 49 * direction handling. Note that you can pass more than a paragraph to this 50 * function and the direction of the first non-neutral paragraph is returned, 51 * which is a very good heuristic to set direction of the neutral paragraphs 52 * at the beginning of text. For other neutral paragraphs, you better use the 53 * direction of the previous paragraph. 54 * 55 * Returns: Base pargraph direction. No weak paragraph direction is returned, 56 * only LTR, RTL, or ON. 57 */ 58 FRIBIDI_ENTRY FriBidiParType fribidi_get_par_direction ( 59 const FriBidiCharType *bidi_types, /* input list of bidi types as returned by 60 fribidi_get_bidi_types() */ 61 const FriBidiStrIndex len /* input string length */ 62 ); 63 64 /* fribidi_get_par_embedding_levels_ex - get bidi embedding levels of a paragraph 65 * 66 * This function finds the bidi embedding levels of a single paragraph, 67 * as defined by the Unicode Bidirectional Algorithm available at 68 * http://www.unicode.org/reports/tr9/. This function implements rules P2 to 69 * I1 inclusive, and parts 1 to 3 of L1, except for rule X9 which is 70 * implemented in fribidi_remove_bidi_marks(). Part 4 of L1 is implemented 71 * in fribidi_reorder_line(). 72 * 73 * There are a few macros defined in fribidi-bidi-types.h to work with this 74 * embedding levels. 75 * 76 * Returns: Maximum level found plus one, or zero if any error occurred 77 * (memory allocation failure most probably). 78 */ 79 FRIBIDI_ENTRY FriBidiLevel 80 fribidi_get_par_embedding_levels_ex ( 81 const FriBidiCharType *bidi_types, /* input list of bidi types as returned by 82 fribidi_get_bidi_types() */ 83 const FriBidiBracketType *bracket_types, /* input list of bracket types as returned by 84 fribidi_get_bracket_types() */ 85 const FriBidiStrIndex len, /* input string length of the paragraph */ 86 FriBidiParType *pbase_dir, /* requested and resolved paragraph 87 * base direction */ 88 FriBidiLevel *embedding_levels /* output list of embedding levels */ 89 ) FRIBIDI_GNUC_WARN_UNUSED; 90 91 /* fribidi_reorder_line - reorder a line of logical string to visual 92 * 93 * This function reorders the characters in a line of text from logical to 94 * final visual order. This function implements part 4 of rule L1, and rules 95 * L2 and L3 of the Unicode Bidirectional Algorithm available at 96 * http://www.unicode.org/reports/tr9/#Reordering_Resolved_Levels. 97 * 98 * As a side effect it also sets position maps if not NULL. 99 * 100 * You should provide the resolved paragraph direction and embedding levels as 101 * set by fribidi_get_par_embedding_levels(). Also note that the embedding 102 * levels may change a bit. To be exact, the embedding level of any sequence 103 * of white space at the end of line is reset to the paragraph embedding level 104 * (That is part 4 of rule L1). 105 * 106 * Note that the bidi types and embedding levels are not reordered. You can 107 * reorder these (or any other) arrays using the map later. The user is 108 * responsible to initialize map to something sensible, like an identity 109 * mapping, or pass NULL if no map is needed. 110 * 111 * There is an optional part to this function, which is whether non-spacing 112 * marks for right-to-left parts of the text should be reordered to come after 113 * their base characters in the visual string or not. Most rendering engines 114 * expect this behavior, but console-based systems for example do not like it. 115 * This is controlled by the FRIBIDI_FLAG_REORDER_NSM flag. The flag is on 116 * in FRIBIDI_FLAGS_DEFAULT. 117 * 118 * Returns: Maximum level found in this line plus one, or zero if any error 119 * occurred (memory allocation failure most probably). 120 */ 121 FRIBIDI_ENTRY FriBidiLevel fribidi_reorder_line ( 122 FriBidiFlags flags, /* reorder flags */ 123 const FriBidiCharType *bidi_types, /* input list of bidi types as returned by 124 fribidi_get_bidi_types() */ 125 const FriBidiStrIndex len, /* input length of the line */ 126 const FriBidiStrIndex off, /* input offset of the beginning of the line 127 in the paragraph */ 128 const FriBidiParType base_dir, /* resolved paragraph base direction */ 129 FriBidiLevel *embedding_levels, /* input list of embedding levels, 130 as returned by 131 fribidi_get_par_embedding_levels */ 132 FriBidiChar *visual_str, /* visual string to reorder */ 133 FriBidiStrIndex *map /* a map of string indices which is reordered 134 * to reflect where each glyph ends up. */ 135 ) FRIBIDI_GNUC_WARN_UNUSED; 136 137 #include "fribidi-enddecls.h" 138 139 #endif /* !_FRIBIDI_BIDI_H */ 140 /* Editor directions: 141 * vim:textwidth=78:tabstop=8:shiftwidth=2:autoindent:cindent 142 */ 143